This Cooperative Research Center proposal is unique in that the proposed projects will almost exclusively involve human subjects. To best accomplish these protocols, this Core has been established specifically for the purpose of recruiting potential subjects and performing screening evaluations to determine their eligibility for inclusion in these studies. The proposed projects will involve two distinct groups of patients. The first will focus on patients allergic to cat allergen, who will be included in the nasal challenge, bronchial challenge, and cat room challenge protocols. These subjects will be recruited either from existing patient databases or by advertisement and will undergo a detailed baseline evaluation in this Core, including skin testing to cat and other common environmental allergens, spirometry, methacholine challenge, measurement of total and allergen-specific serum IgE levels and histamine releasing factor, blood basophil studies, and nasal challenge with cat allergen. Those who meet the inclusion and exclusion criteria as detailed in the protocols will be invited to participate in one or more of those studies. The second group of patients will include those with a known allergy to milk, egg, or peanut. They will also be recruited from existing patient databases or by advertisement. Their evaluation will include skin testing to the relevant food allergen(s) and environmental allergens, spirometry, measurement of total and allergen-specific serum IgE levels and histamine releasing factor, blood basophil studies, and double-blind, placebo-controlled food challenges to the food(s) in question. Those who meet the inclusion and exclusion criteria as detailed in the protocol will be invited to participate in the food challenge study. In addition to its role in the recruitment and evaluation of potential study subjects, this Core will assume primary responsibility for the Center for issues regarding patient safety and regulatory affairs. For this reason, the Core's personnel include a regulatory affairs specialist who will meet regularly with the principal investigator to oversee these issues and serve as a liaison between the Center, the IRB, and the FDA.